This study aimed to compare terrestrial insect communities in forests and grasslands to explore habitat-specific differences. Grassland and undisturbed forest zones in Buk-sil-ri, Jeongseon-eup, Gangwon-do were surveyed in August and September of 2022 and 2023 using visual inspection and light traps. A total of 1,369 individuals from 447 species, 56 families, and 13 orders were recorded. Lepidoptera was the most dominant (44.0%, with 239 species and 602 individuals) order, followed by Hemiptera (17.6%, 81 species and 241 individuals) and Odonata (11.4%, 13 species and 156 individuals). While most orders, including Lepidoptera, Hemiptera, and Diptera, showed higher abundance and richness in forests than in grasslands, the diversity index was greater in grasslands. The presence of diverse vegetation including invasive species in grasslands likely influenced insect diversity and composition. These findings can enhance our understanding of insect community dynamics across forest and grassland habitats.